1. Field of the Invention
The present invention concerns a timepiece, in particular a wristwatch, whose dial can be exchanged. It also concerns a dial designed for a timepiece with interchangeable dial.
2. Description of the Related Art
The dial of a watch is one of the main pieces determining the aesthetic aspect of the watch. Consequently, rather than owning several different watches, it can be interesting for the user to be able to change the dial of his watch in order to modify its aspect according to circumstances and fashion. Thus, the owner of a watch according to the invention could have for example a dial reminiscent of the sport he engages in as well as another dial adapted to his job and yet other dials devised for other circumstances of his life.
Several attempts have been made to propose watches of this type. For example, documents FR-A-2.746.499 and U.S. Pat. No. 6,118,735 each describe a timepiece comprising a lateral slit allowing a removable dial to be inserted or removed. In the pieces of this type, the slit on the one hand always remains visible, which is not aesthetically pleasing, and on the other hand always remains accessible and at least partially open, which allows humidity and dust to penetrate under the watch's glass. Furthermore, the systems for fastening the dial to the case being very crude and poorly reliable, the risk of losing the dial when shaking the wrist is not negligible.
The watches described in FR-A-2.614.443 and U.S. Pat. No. 4,660,992 comprise a lateral portion of the case body, mounted pivotally by one extremity on the rest of the case body, so as to free or hide a lateral slit for inserting or removing the dial. Although the aesthetic aspect is more elaborate than in the preceding watches, fastening a relatively large portion of the case body onto the rest of the case body by means of a hinge of small dimensions constitutes a weak point in this kind of watch. Indeed, as soon as the case body is open, and in view of the considerable leverage exerted by the open lateral portion of this case body on the hinge, the latter is very quickly subjected to deformations which makes it impossible to close the watch again. Furthermore, such a device does not allow the dial's insertion slit to be easily made tight.
Patent U.S. Pat. No. 5,793,710 describes a watch having an interchangeable dial that is flexible and provided with a narrow slit that can deform to allow the hands' axis to pass. This way of proceeding risks damaging the hands' axis if the dial is changed often. Furthermore, since the dial is flexible and can easily deform, this device requires a transparent protection to be interposed between the dial and the hands in order to protect the latter. The closure device described in this document comprises two elastic fastening devices placed at the two extremities of a detachable portion of the case body to which the interchangeable dial is fastened. This arrangement is difficult to use inasmuch as it is necessary to operate simultaneously two push buttons of very small dimensions.